Wiktionary
the dear knows
phr. 1 (context Ireland dated English) God knows; nobody knows 2 (context Ireland dated English) God knows; of course, certainly, nobody could doubt
Usage examples of "the dear knows".
Though the Dear knows, I believe I should sleep through ten bands playing in the corridor.
Have I not been searching every nook and cranny in this vile tub and the Dear knows she has a thousand of both systematically searching for my rosin, my only piece of rosin since an ill-conditioned rat ate the others.
You have been wounded the Dear knows how many times, and you have been cruelly overworked.
I cannot recall an instance in all my time at sea, though the Dear knows I have seen a terrible lot of punishment.